1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *    http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdio.h>
18#include <string.h>
19#include <errno.h>
20#include <limits.h>
21#include <stdlib.h>
22
23#include "private/android_filesystem_config.h"
24
25#include "canned_fs_config.h"
26
27typedef struct {
28	const char* path;
29	unsigned uid;
30	unsigned gid;
31	unsigned mode;
32	uint64_t capabilities;
33} Path;
34
35static Path* canned_data = NULL;
36static int canned_alloc = 0;
37static int canned_used = 0;
38
39static int path_compare(const void* a, const void* b) {
40	return strcmp(((Path*)a)->path, ((Path*)b)->path);
41}
42
43int load_canned_fs_config(const char* fn) {
44	FILE* f = fopen(fn, "r");
45	if (f == NULL) {
46		fprintf(stderr, "failed to open %s: %s\n", fn, strerror(errno));
47		return -1;
48	}
49
50	char line[PATH_MAX + 200];
51	while (fgets(line, sizeof(line), f)) {
52		while (canned_used >= canned_alloc) {
53			canned_alloc = (canned_alloc+1) * 2;
54			canned_data = (Path*) realloc(canned_data, canned_alloc * sizeof(Path));
55		}
56		Path* p = canned_data + canned_used;
57		p->path = strdup(strtok(line, " "));
58		p->uid = atoi(strtok(NULL, " "));
59		p->gid = atoi(strtok(NULL, " "));
60		p->mode = strtol(strtok(NULL, " "), NULL, 8);   // mode is in octal
61		p->capabilities = 0;
62
63		char* token = NULL;
64		do {
65			token = strtok(NULL, " ");
66			if (token && strncmp(token, "capabilities=", 13) == 0) {
67				p->capabilities = strtoll(token+13, NULL, 0);
68				break;
69			}
70		} while (token);
71
72		canned_used++;
73	}
74
75	fclose(f);
76
77	qsort(canned_data, canned_used, sizeof(Path), path_compare);
78	printf("loaded %d fs_config entries\n", canned_used);
79
80	return 0;
81}
82
83void canned_fs_config(const char* path, int dir,
84					  unsigned* uid, unsigned* gid, unsigned* mode, uint64_t* capabilities) {
85	Path key;
86	key.path = path+1;   // canned paths lack the leading '/'
87	Path* p = (Path*) bsearch(&key, canned_data, canned_used, sizeof(Path), path_compare);
88	if (p == NULL) {
89		fprintf(stderr, "failed to find [%s] in canned fs_config\n", path);
90		exit(1);
91	}
92	*uid = p->uid;
93	*gid = p->gid;
94	*mode = p->mode;
95	*capabilities = p->capabilities;
96
97#if 0
98	// for debugging, run the built-in fs_config and compare the results.
99
100	unsigned c_uid, c_gid, c_mode;
101	uint64_t c_capabilities;
102	fs_config(path, dir, &c_uid, &c_gid, &c_mode, &c_capabilities);
103
104	if (c_uid != *uid) printf("%s uid %d %d\n", path, *uid, c_uid);
105	if (c_gid != *gid) printf("%s gid %d %d\n", path, *gid, c_gid);
106	if (c_mode != *mode) printf("%s mode 0%o 0%o\n", path, *mode, c_mode);
107	if (c_capabilities != *capabilities) printf("%s capabilities %llx %llx\n", path, *capabilities, c_capabilities);
108#endif
109}
110